PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "SFH 2006-09-27 2012-09-14 SBN:T.Barnes Removed DATA_SET_ID. 2017-02-24 CG/CT: removed wrong info in INSTRUMENT_DESC and refer to Keller et al." RECORD_TYPE = STREAM OBJECT = INSTRUMENT INSTRUMENT_HOST_ID = "RO" INSTRUMENT_ID = "OSIWAC" OBJECT = INSTRUMENT_INFORMATION INSTRUMENT_NAME = "OSIRIS - WIDE ANGLE CAMERA" INSTRUMENT_TYPE = "FRAME CCD REFLECTING TELESCOPE" INSTRUMENT_DESC = " The instrument was provided by the OSIRIS consortium led by the principal investigator Dr. Horst Uwe Keller. The OSIRIS consortium have the following members: MPS Overall responsibility and project management, system engineering, interfaces, Focal Plane Assemblies, CCDs and Readout Boards, HK Boards, integration and qualification of E-Boxes, harnesses, system integration, high level software, NAC & WAC system calibration, QA, mission operations LAM NAC telescope, camera integration and qualification WAC optical bench, camera UPD Integration and qualification, shutter mechanisms and shutter electronics, Front Door Mechanisms (mechanisms for NAC and WAC) IAA Mechanism Controller Board INTA Filter Wheel Mechanisms, E-Box Power Converter Module, NAC & WAC CRB Power Converter Modules RSSD Data Processing Unit IDA Mass memory, low level software and data compression DASP NAC & WAC Filters UPM Thermal and structural analysis, NAC MLI, WAC FPA MLI For detailed instrument description please see the Space Science Review Paper by Keller et al. (2007) included in the dataset (DOCUMENT/OSIRIS_SSR/KELLER_ET_AL_2007_V01.PDF). OSIRIS, the Optical, Spectroscopic, and Infrared Remote Imaging System is the scientific camera system on board Rosetta. It comprises a Narrow Angle Camera (NAC) and a Wide Angle Camera (WAC) with a field of view (FOV) of 2.20 degree times 2.22 degree and 11.35 degree times 12.11 degree, respectively, and an instantaneous field of view (IFOV) of 18.6 microradian per pixel and of 101.0 microradian per pixel, respectively. Both cameras use a 2048 times 2048 pixel backside illuminated CCD detector with a UV optimized anti-reflection coating. The CCDs are equipped with lateral anti-blooming that allows overexposure of the nucleus without creating saturation artifacts, enabling the study of details in the faint coma structures next to the illuminated limb. The CCD full well capacity is smaller than 120000 electrons per pixel (Keller et al. 2007). The pixel linearity is guaranteed only below this limit. A gain value of 3.1 electrons per DN (DN = digital number) in HIGH gain mode and 15.5 electrons per DN in LOW gain mode is used, as specified by the manufacturer. Calibration images to measure the gain were acquired in December 2014, and will be used to investigate whether an update to the current gain values is needed. The NAC and WAC are equipped with two readout ampli?ers each that can be used independently or together to achieve a faster readout of the image. Both cameras are off-axis systems, with no central obscuration along the beam. The off-axis design has the advantage of providing high transmittance from the UV to the near-IR and diffraction limited performance with low geometrical optical aberration, but introduces a significant geometric distortion that needs to be corrected for scientific use of the image products. The NAC is equipped with 11 filters covering a wavelength range of 250 nanometer to 1000 nanometer, while the WAC has 14 filters covering a range of 240 nanometer to 720 nanometer. The transmission curves of the NAC and WAC filters can be found in Figure 1 of Tubiana et al. 2015 included in the dataset (DOCUMENT/CALIB/TUBIANA_ET_AL_2015_V01.PDF). In addition to the bandpass filters, the NAC filter wheels contain a neutral density filter and anti-reflection coated focus plates: three far focus plates (FFP-UV, FFP-VIS, and FFP-IR) and a near focus plate (NFP-VIS). The focus plates, combined with the bandpass filters, allow two focusing ranges: far focus from infinity to 2 kilometer, optimized at 4 kilometer, and near focus from 2 kilometer to 1 kilometer, optimized at 1.3 kilometer. Both cameras have a plane-parallel 12 millimeter thick anti-reflection coated plate (ARP) in front of the CCD for radiation shielding. The transmission curves of the focus plates, the anti-reflection coated plates, together with the total reflectivity of the mirror system and the quantum efficiency of the CCD are plotted in Figure 1 of Tubiana et al. 2015. The NAC and WAC have been designed as a complementary pair that addresses, on the one hand, the study of the nucleus surface, and, on the other hand, the investigation of the dynamics of the sublimation processes. The NAC, with its high spatial resolution, was used to detect the nucleus of 67P/Churyumov-Gerasimenko from a distance of millions of kilometers, and it is now used to study the morphology and mineralogy of the surface and details of the dust ejection process. The WAC has a lower spatial resolution and, accordingly, a much wider field of view. This allows observations of the 3D flow-field of dust and gas even if the spacecraft is near the nucleus and provides a synoptic view of the nucleus for context of the NAC and other instruments onboard Rosetta. To summarize, the WAC provides long-term monitoring of the entire nucleus and its surrounding, while the NAC studies the surface details. " END_OBJECT = INSTRUMENT_INFORMATION OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "KELLERETAL2006" END_OBJECT = INSTRUMENT_REFERENCE_INFO END_OBJECT = INSTRUMENT END